The right to use water is private property in the West, and no one is allowed to use water without buying water rights first. This means that beaver are water thieves: all of the water they impound is actually owned by someone downstream, and by gum ranchers aren’t going to be thwarted by some damned rodent. In Colorado, beaver (like prairie dogs) are classified as pests.
I agree that it looks as though beaver are water hoarders, taking more than their fair share of a scarce resource. But with water, it’s often true that what’s going on underground trumps what we see on the surface.
This illustration is by Steve Grannes, University of Minnesota MS Agricultural Engineering 1984. Here we have two streams coming straight out of the page, and let’s pretend for the sake of this discussion that they’re several miles apart.
When you add a beaver dam to one of the streams, it backs up water behind the dam and more water seeps down to the groundwater. This dam actually raises the level of the water table underground, which increases the flow of springs and streams in the surrounding area.
This means that beaver dams upstream should actually increase the flow of water downstream: add beavers, and you get more water in the watershed, not less. And a three year research project completed in 2006 shows that is exactly what happens. In the Rocky Mountain National Park, researchers found that ponds created by beaver dams in the Colorado River Valley raised the water table downstream, and increased the level of soil moisture far below the dams.
What is true in theory has been shown to be true in practice. In arid regions, beavers don’t steal the water in the river. Instead, their dams enhance downstream flows.
When ranchers insist that beaver populations or prairie dogs populations imperil their livelihood (as everyone knows) I can only say that when it comes to water, things are seldom what they seem,
or,
who you gonna believe: me Dr. Cherie Westbrook, or your lying eyes?
(Beaver Symbol, Pacific Northwest)
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